I just found this vmware knowledge base article in the web Slow performance during Storage vMotion, Clone, and Snapshot consolidation operations in various storage systems (2007723) I think one of the solutions to this problem can be found in the behavior that we have described here The bad thing for this is - you will probably not see this problem when you cannot go deeper into the system. Performance Analysis VAAI undercover write operations Performance Bottleneck Analysis- VAAI undercover write operations In this example... [More]

This is a small history of changes we saw in a customer situation with several performance issues in a VMware environment. In the beginning the customer had Buffer Credit Waits of more than 51%. This means that in the timeframe (5 minutes every morning – see needles) the SAN was only available half of the time to accept writes. We gave the customer 3 tips to improve this situation Rebalance the load on the node ports Reduce SAN traffic between the SVC nodes – do not address the “non preferred node” in this case... [More]

I'm really excited about this next option in our mdisk group analysis section. It is the first time that we can analyse into the internal SVC queues down to the storage system. With this new option we get a much better view of the performance problems of the storage system. It is obvious that this backend storage system was in deep performance troubles from 5 am to 6:30 am. Have a look to this: The picture belongs to this whitepaper ... [More]

Sometimes dead links happen - we had 2 dead links on the page which have been fixed right now! The german version of the article was missing. The external connection to searchstorage was broken rue to the fact that they have been renamed to datacenter.insider.de - I still have an issue because the first half ot the article is still mjissing. I am in contact with them to fix this. BVQ Use Case: Performance Bottleneck Analysis on IBM SVC and IBM Storwize

With using min and max cache fullness values one can better analysis what is going on in the SVC or Storwize cache. This is espacially helpful when you want to find the root causes of performance bottleneck. http://bvqwiki.sva.de/x/AwCW This document belongs to the BVQ Use Case Performance Analysis http://bvqwiki.sva.de/x/e4E6